1. Field of the Invention
The present invention relates to spatial light modulators and, more specifically, to a novel high-speed, spatial light modulator using electron trapping materials.
2. Description of the Related Art
Spatial light modulators are devices that modify the phase, polarization, amplitude, or intensity of a one-dimensional or two-dimensional readout light distribution as a function of space and time. Such modulators can be electrically or optically addressed Most are based on polarization modulation generated by electrooptic or other effects. The proper orientation of an analyzer between the spatial light modulator and a detector will further result in either phase or amplitude modulation.
Another class of spatial light modulators relies on the volume grating generated in photo-refractive materials. Recently, fast response, multiple quantum well spatial light modulators that make use of direct energy absorption in III-V compounds to modulate the light amplitude have been proposed and demonstrated. Fabrication of these types of modulators is based on a sophisticated semiconductor technology, e.g., molecular beam epitaxy of alternating thin layers of III-V compounds. For a more detailed description of prior art spatial light modulators and multiple quantum well structures, see A. R. Tanguay, Jr., "Materials Requirements for Optical Processing and Computing Devices," Optical Engineering, Jan./Feb. 1985, Vol. 24, No. 1, pp. 002-018, herein incorporated by reference.
Although spatial light modulation by direct energy absorption is highly desirable because of its relatively high speed and fine resolution, the fabrication of multiple quantum well structures is complicated and expensive. Accordingly, it would be desirable if this function could be performed by a material deposited in a simple, thin film layer.